Delay x0 12-Bit Grayscale PWM Control DC Register GS Register DC EEPROM Constant Current Driver LED Open Detection Temperature Error Flag (TEF) Max. OUTn Current Delay x1 12-Bit Grayscale PWM Control DC Register GS Register DC EEPROM Constant Current Driver LED Open Detection Delay x15 6-Bit Dot 12-Bit Grayscale PWM Control DC Register GS Register DC EEPROM Constant Current Driver LED Open Detection OUT0 OUT1 OUT15 SOUT SIN SCLK IREF XERR XLAT GSCLK BLANK DCPRG DCPRG DCPRG VPRG VPRG VPRG GND VCC VPRG Input Shift Register Input Shift Register VPRG 11 0 23 12 191 180 95 90 11 6 5 VPRG 0 0 95 96 191 LED Open Detection (LOD) 5 95 90 6 11 DCPRG 0 192 96 0 1 0 1 0 1 0 1 GS Counter CNT CNT CNT CNT 96 96 Status Information: LOD, TED, DC DATA 192 0 191 1 0 0 1 V REF =1.24 V Correction 6-Bit Dot Correction 6-Bit Dot Correction 0 1 Blank Product Folder Sample & Buy Technical Documents Tools & Software Support & Community TLC5940 SLVS515D – DECEMBER 2004 – REVISED NOVEMBER 2015 TLC5940 16-Channel LED Driver With DOT Correction and Grayscale PWM Control 1 Features 3 Description The TLC5940 is a 16-channel, constant-current sink 1• 16 Channels LED driver. Each channel has an individually • 12 bit (4096 Steps) Grayscale PWM Control adjustable 4096-step grayscale PWM brightness • Dot Correction control and a 64-step, constant-current sink (dot correction). The dot correction adjusts the brightness – 6 bit (64 Steps) variations between LED channels and other LED – Storable in Integrated EEPROM drivers. The dot correction data is stored in an • Drive Capability (Constant-Current Sink) integrated EEPROM. Both grayscale control and dot correction are accessible through a serial interface. A – 0 mA to 60 mA (V CC < 3.6 V) single external resistor sets the maximum current – 0 mA to 120 mA (V CC > 3.6 V) value of all 16 channels. • LED Power Supply Voltage up to 17 V The TLC5940 features two error information circuits. • V CC = 3 V to 5.5 V The LED open detection (LOD) indicates a broken or • Serial Data Interface disconnected LED at an output terminal. The thermal error flag (TEF) indicates an overtemperature • Controlled In-Rush Current condition. • 30 MHz Data Transfer Rate • CMOS Level I/O Device Information (1) • Error Information PART NUMBER PACKAGE BODY SIZE (NOM) – LOD: LED Open Detection PDIP (28) 35.69 mm × 6.73 mm – TEF: Thermal Error Flag TLC5940 HTSSOP (28) 9.70 mm × 4.40 mm VQFN (32) 5.00 mm × 5.00 mm 2 Applications (1) For all available packages, see the orderable addendum at the end of the datasheet. • Monocolor, Multicolor, Full-Color LED Displays • LED Signboards • Display Backlighting • General, High-Current LED Drive Block Diagram 1 An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications, intellectual property matters and other important disclaimers. PRODUCTION DATA.
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Delayx0
12−Bit Grayscale
PWM Control
DC Register
GS Register
DC EEPROM
Constant CurrentDriver
LED Open Detection
TemperatureError Flag
(TEF)
Max. OUTnCurrent
Delayx1
12−Bit GrayscalePWM Control
DC Register
GS Register
DC EEPROM
Constant CurrentDriver
LED Open Detection
Delayx15
6−Bit Dot
12−Bit Grayscale
PWM Control
DC Register
GS Register
DC EEPROM
Constant CurrentDriver
LED Open Detection
OUT0
OUT1
OUT15
SOUT
SINSCLK
IREF
XERR
XLAT
GSCLK
BLANK
DCPRG
DCPRG
DCPRG
VPRG
VPRG
VPRG
GNDVCC
VPRG
InputShift
Register
InputShift
Register
VPRG 110
2312
191180
9590
116
5
VPRG
0
0
95
96
191
LED OpenDetection
(LOD)
5
9590
6 11
DCPRG
0
192
96
01
01 0
1
01
GS Counter CNT
CNT
CNT
CNT
96
96
StatusInformation:
LOD,TED,
DC DATA
192
0
191
1
0
0
1
VREF =1.24 V
Correction
6−Bit DotCorrection
6−Bit DotCorrection
01
Blank
Product
Folder
Sample &Buy
Technical
Documents
Tools &
Software
Support &Community
TLC5940SLVS515D –DECEMBER 2004–REVISED NOVEMBER 2015
TLC5940 16-Channel LED Driver With DOT Correction and Grayscale PWM Control1 Features 3 Description
The TLC5940 is a 16-channel, constant-current sink1• 16 Channels
LED driver. Each channel has an individually• 12 bit (4096 Steps) Grayscale PWM Control adjustable 4096-step grayscale PWM brightness• Dot Correction control and a 64-step, constant-current sink (dot
correction). The dot correction adjusts the brightness– 6 bit (64 Steps)variations between LED channels and other LED– Storable in Integrated EEPROM drivers. The dot correction data is stored in an
• Drive Capability (Constant-Current Sink) integrated EEPROM. Both grayscale control and dotcorrection are accessible through a serial interface. A– 0 mA to 60 mA (VCC < 3.6 V)single external resistor sets the maximum current– 0 mA to 120 mA (VCC > 3.6 V)value of all 16 channels.
• LED Power Supply Voltage up to 17 VThe TLC5940 features two error information circuits.• VCC = 3 V to 5.5 V The LED open detection (LOD) indicates a broken or
• Serial Data Interface disconnected LED at an output terminal. The thermalerror flag (TEF) indicates an overtemperature• Controlled In-Rush Currentcondition.• 30 MHz Data Transfer Rate
• CMOS Level I/O Device Information(1)
• Error Information PART NUMBER PACKAGE BODY SIZE (NOM)– LOD: LED Open Detection PDIP (28) 35.69 mm × 6.73 mm– TEF: Thermal Error Flag TLC5940 HTSSOP (28) 9.70 mm × 4.40 mm
VQFN (32) 5.00 mm × 5.00 mm2 Applications
(1) For all available packages, see the orderable addendum atthe end of the datasheet.• Monocolor, Multicolor, Full-Color LED Displays
• LED Signboards• Display Backlighting• General, High-Current LED Drive
Block Diagram
1
An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,intellectual property matters and other important disclaimers. PRODUCTION DATA.
10 Power Supply Recommendations ..................... 256.1 Absolute Maximum Ratings ...................................... 511 Layout................................................................... 256.2 ESD Ratings.............................................................. 5
11.1 Layout Guidelines ................................................. 256.3 Recommended Operating Conditions....................... 511.2 Layout Example .................................................... 256.4 Thermal Information .................................................. 611.3 Power Dissipation Calculation .............................. 266.5 Electrical Characteristics........................................... 7
12 Device and Documentation Support ................. 276.6 Switching Characteristics .......................................... 812.1 Community Resources.......................................... 276.7 Typical Characteristics .............................................. 912.2 Trademarks ........................................................... 277 Parameter Measurement Information ................ 1112.3 Electrostatic Discharge Caution............................ 277.1 Test Parameter Equations ...................................... 1212.4 Glossary ................................................................ 278 Detailed Description ............................................ 13
13 Mechanical, Packaging, and Orderable8.1 Overview ................................................................. 13Information ........................................................... 27
4 Revision HistoryNOTE: Page numbers for previous revisions may differ from page numbers in the current version.
Changes from Revision C (October 2007) to Revision D Page
• Added ESD Ratings table, Feature Description section, Device Functional Modes, Application and Implementationsection, Power Supply Recommendations section, Layout section, Device and Documentation Support section, andMechanical, Packaging, and Orderable Information section. ................................................................................................. 1
Changes from Revision B (September 2007) to Revision C Page
• Changed tsu5 setup time from: 30 ms to: 30 ns ...................................................................................................................... 6
TLC5940SLVS515D –DECEMBER 2004–REVISED NOVEMBER 2015 www.ti.com
Pin FunctionsPIN
TYPE DESCRIPTIONNAME DIP NO. PWP NO. RHB NO.
Blank all outputs. When BLANK = H, all OUTn outputs are forced OFF.BLANK 23 2 31 I GS counter is also reset. When BLANK = L, OUTn are controlled by
grayscale PWM control.Switch DC data input. When DCPRG = L, DC is connected toEEPROM. When DCPRG = H, DC is connected to the DC register.DCPRG 19 26 25 I DCPRG also controls EEPROM writing, when VPRG = V(PRG).EEPROM data = 3 Fh (default)
GND 22 1 30 G GroundGSCLK 18 25 24 I Reference clock for grayscale PWM controlIREF 20 27 26 I Reference current terminal
— — 12— — 13
NC — No connection— — 28— — 29
OUT0 28 7 4 O Constant current outputOUT1 1 8 5 O Constant current outputOUT2 2 9 6 O Constant current outputOUT3 3 10 7 O Constant current outputOUT4 4 11 8 O Constant current outputOUT5 5 12 9 O Constant current outputOUT6 6 13 10 O Constant current outputOUT7 7 14 11 O Constant current outputOUT8 8 15 14 O Constant current outputOUT9 9 16 15 O Constant current outputOUT10 10 17 16 O Constant current outputOUT11 11 18 17 O Constant current outputOUT12 12 19 18 O Constant current outputOUT13 13 20 19 O Constant current outputOUT14 14 21 20 O Constant current outputOUT15 15 22 21 O Constant current outputSCLK 25 4 1 I Serial data shift clockSIN 26 5 2 I Serial data inputSOUT 17 24 23 O Serial data outputVCC 21 28 27 I Power supply voltage
Multifunction input pin. When VPRG = GND, the device is in GS mode.When VPRG = VCC, the device is in DC mode. When VPRG = V(VPRG),VPRG 27 6 3 I DC register data can programmed into DC EEPROM withDCPRG=HIGH. EEPROM data = 3 Fh (default)Error output. XERR is an open-drain terminal. XERR goes L when LODXERR 16 23 22 O or TEF is detected.Level triggered latch signal. When XLAT = high, the TLC5940 writesdata from the input shift register to either GS register (VPRG = low) orXLAT 24 3 32 I DC register (VPRG = high). When XLAT = low, the data in GS or DCregister is held constant.
V(OUT0) to V(OUT15) –0.3 18 VOutput current (dc) 130 mAEEPROM program range V(VPRG) –0.3 24 VEEPROM write cycles 50 —Storage temperature, Tstg –55 150 °C
(1) Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratingsonly, which do not imply functional operation of the device at these or any other conditions beyond those indicated under RecommendedOperting Conditions. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
(2) All voltage values are with respect to network ground terminal.
6.2 ESD RatingsVALUE UNIT
Human-body model (HBM), per ANSI/ESDA/JEDEC JS-001 (1) ±2000V(ESD) Electrostatic discharge VCharged-device model (CDM), per JEDEC specification JESD22- ±500
C101 (2)
(1) JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process.(2) JEDEC document JEP157 states that 250-V CDM allows safe manufacturing with a standard ESD control process.
6.3 Recommended Operating ConditionsMIN NOM MAX UNIT
DC CHARACTERISTICSVCC Supply Voltage 3 5.5 VV O Voltage applied to output (OUT0–OUT15) 17 VVIH High-level input voltage 0.8 VCC VCC VVIL Low-level input voltage GND 0.2 VCC VIOH High-level output current VCC = 5 V at SOUT –1 mAIOL Low-level output current VCC = 5 V at SOUT, XERR 1 mA
OUT0 to OUT15, VCC < 3.6 V 60 mAIOLC Constant output current
OUT0 to OUT15, VCC > 3.6 V 120 mAV(VPRG) EEPROM program voltage 20 22 23 VTA Operating free-air temperature range -40 85 °CAC CHARACTERISTICSVCC = 3 V to 5.5 V, TA = –40°C to 85°C (unless otherwise noted)f(SCLK) Data shift clock frequency SCLK 30 MHzf(GSCLK) Grayscale clock frequency GSCLK 30 MHztwh0/twl0 SCLK pulse duration SCLK = H/L (see Figure 11) 16 nstwh1/twl1 GSCLK pulse duration GSCLK = H/L (see Figure 11) 16 nstwh2 XLAT pulse duration XLAT = H (see Figure 11) 20 nstwh3 BLANK pulse duration BLANK = H (see Figure 11) 20 ns
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Recommended Operating Conditions (continued)MIN NOM MAX UNIT
tsu0 SIN to SCLK ↑ (1) (see Figure 11) 5 nstsu1 SCLK ↓ to XLAT ↑ (see Figure 11) 10 nstsu2 VPRG ↑ ↓ to SCLK ↑ (see Figure 11) 10 nstsu3 Setup time VPRG ↑ ↓XLAT ↑ (see Figure 11) 10 nstsu4 BLANK ↓ to GSCLK ↑ (see Figure 11) 10 nstsu5 XLAT ↑ to GSCLK ↑ (see Figure 11) 30 nstsu6 VPRG ↑ to DCPRG ↑ (see Figure 16) 1 msth0 SCLK ↑ to SIN (see Figure 11) 3 nsth1 XLAT ↓ to SCLK ↑ (see Figure 11) 10 nsth2 SCLK ↑ to VPRG ↑ ↓ (see Figure 11) 10 ns
Hold Timeth3 XLAT ↓ to VPRG ↑ ↓ (see Figure 11) 10 nsth4 GSCLK ↑ to BLANK ↑ (see Figure 11) 10 nsth5 DCPRG ↓ to VPRG ↓ (see Figure 11) 1 mstprog Programming time for EEPROM (see Figure 16) 20 ms
(1) ↑ and ↓ indicates a rising edge, and a falling edge respectively.
TLC5940www.ti.com SLVS515D –DECEMBER 2004–REVISED NOVEMBER 2015
6.5 Electrical CharacteristicsVCC = 3 V to 5.5 V, TA = –40°C to 85°C (unless otherwise noted)
PARAMETER TEST CONDITIONS MIN TYP MAX UNITVOH High-level output voltage IOH = -1 mA, SOUT VCC –0.5 VVOL Low-level output voltage IOL = 1 mA, SOUT 0.5 V
VI = VCC or GND; BLANK, DCPRG, GSCLK, SCLK, SIN, –1 1XLATμAVI = GND; VPRG –1 1II Input current
VI = VCC; VPRG 50VI = 22 V; VPRG; DCPRG = VCC 4 10 mANo data transfer, all output OFF, 0.9 6VO = 1 V, R(IREF) = 10 kΩNo data transfer, all output OFF, 5.2 12VO = 1 V, R(IREF) = 1.3 kΩ
ICC Supply current mAData transfer 30MHz, all output ON, 16 25VO = 1 V, R(IREF) = 1.3 kΩData transfer 30MHz, all output ON, 30 60VO = 1 V, R(IREF) = 640 Ω
Constant sink current (seeIO(LC) All output ON, VO = 1 V, R(IREF) = 640 Ω 54 61 69 mAFigure 10)All output OFF, VO = 15 V, R(IREF) = 640 Ω,Ilkg Leakage output current 0.1 μAOUT0 to OUT15All output ON, VO = 1 V, R(IREF) = 640 Ω, ±1% ±4%OUT0 to OUT15, –20°C to 85°CAll output ON, VO = 1V, R(IREF) = 640 Ω, ±1% ±8%OUT0 to OUT15 (1)Constant sink current errorΔIO(LC0) (see Figure 10) All output ON, VO = 1V, R(IREF) = 320 Ω, ±1% ±6%OUT0 to OUT15, –20°C to 85°CAll output ON, VO = 1V, R(IREF) = 320 Ω, ±1% ±8%VCC = 4.5 V to 5.5 V, OUT0 to OUT15 (1)
–2%Constant sink current error Device to device, Averaged current from OUT0 toΔIO(LC1) ±4%(see Figure 10) OUT15, R(IREF) = 1920 Ω (20 mA) (2) +0.4%–2.7%Constant sink current error Device to device, Averaged current from OUT0 toΔIO(LC2) ±4%(see Figure 10) OUT15, R(IREF) = 480 Ω (80 mA) (2) +2%
All output ON, VO = 1V, R(IREF) = 640 Ω ±1 ±4 %/VOUT0 to OUT15, VCC = 3 V to 5.5 V (3)ΔIO(LC3) Line regulation (see Figure 10)
All output ON, VO = 1V, R(IREF) = 320 Ω , ±1 ±6 %/VOUT0 to OUT15, VCC = 3 V to 5.5 V (3)
All output ON, VO = 1 V to 3 V, R(IREF) = 640 Ω, ±2 ±6 %/VOUT0 to OUT15 (4)Load regulation (seeΔIO(LC4) Figure 10) All output ON, VO = 1 V to 3 V, R(IREF) = 320 Ω, ±2 ±8 %/VOUT0 to OUT15 (4)
T(TEF) Thermal error flag threshold Junction temperature (5) 150 170 °CV(LED) LED open detection threshold 0.3 0.4 V
(1) The deviation of each output from the average of OUT0-15 constant current. It is calculated by Equation 1 in Test Parameter Equations.(2) The deviation of average of OUT1-15 constant current from the ideal constant-current value. It is calculated by Equation 2 in Test
Parameter Equations. The ideal current is calculated by Equation 3 in Test Parameter Equations.(3) The line regulation is calculated by Equation 4 in Test Parameter Equations.(4) The load regulation is calculated by Equation 5 in Test Parameter Equations.(5) Not tested. Specified by design
TLC5940SLVS515D –DECEMBER 2004–REVISED NOVEMBER 2015 www.ti.com
6.6 Switching CharacteristicsVCC = 3V to 5.5V, TA = -40°C to 85°C (unless otherwise noted)
PARAMETER TEST CONDITIONS MIN TYP MAX UNITtr0 SOUT 16
Rise time nstr1 OUTn, VCC = 5 V, TA = 60°C, DCn = 3 Fh 10 30tf0 SOUT 16
Fall time nstf1 OUTn, VCC = 5 V, TA = 60°C, DCn = 3 Fh 10 30tpd0 SCLK to SOUT (see Figure 11) 30 nstpd1 BLANK to OUT0 60 nstpd2 OUTn to XERR (see Figure 11) 1000 ns
Propagation delay timetpd3 GSCLK to OUT0 (see Figure 11) 60 nstpd4 XLAT to IOUT (dot correction) (see Figure 11) 60 nstpd5 DCPRG to OUT0 (see Figure 11) 30 nstd Output delay time OUTn to OUT(n+1) (see Figure 11) 20 30 nston-err Output on-time error touton– Tgsclk (see Figure 11), GSn = 01h, GSCLK = 11 MHz 10 –50 –90 ns
TLC5940www.ti.com SLVS515D –DECEMBER 2004–REVISED NOVEMBER 2015
8 Detailed Description
8.1 OverviewThe TLC5940 is a 16-channel constant current sink driver. Each channel has an individually-adjustable, 4096-step, pulse width modulation (PWM), grayscale (GS) brightness control, and a 64-step dot correction brightnesscontrol. GS data and DC data are input via a serial interface port. The dot correction data is stored in anintegrated EEPROM. The TLC5940 has a 120-mA current capability. The maximum current value of all channelsis determined by an external resistor. The TLC5940 has a LED open detection (LOD) function that indicates abroken or disconnected LED at an output terminal and a thermal error flag (TEF) indicates an overtemperaturecondition.
8.2 Functional Block Diagram
8.3 Feature Description
8.3.1 Serial InterfaceThe TLC5940 has a flexible serial interface, which can be connected to microcontrollers or digital signalprocessors in various ways. Only 3 pins are needed to input data into the device. The rising edge of SCLK signalshifts the data from the SIN pin to the internal register. After all data is clocked in, a high-level pulse of XLATsignal latches the serial data to the internal registers. The internal registers are level-triggered latches of XLATsignal. All data are clocked in with the MSB first. The length of serial data is 96 bit or 192 bit, depending on theprogramming mode. Grayscale data and dot correction data can be entered during a grayscale cycle. Althoughnew grayscale data can be clocked in during a grayscale cycle, the XLAT signal should only latch the grayscaledata at the end of the grayscale cycle. Latching in new grayscale data immediately overwrites the existinggrayscale data. Figure 11 shows the timing chart. More than two TLC5940s can be connected in series byconnecting an SOUT pin from one device to the SIN pin of the next device. An example of cascading twoTLC5940s is shown in Figure 12 and the timing chart is shown in Figure 13. The SOUT pin can also beconnected to the controller to receive status information from TLC5940 as shown in Figure 22.
TLC5940www.ti.com SLVS515D –DECEMBER 2004–REVISED NOVEMBER 2015
Feature Description (continued)
Figure 13. Timing Chart for Two Cascaded TLC5940 Devices
8.3.2 Error Information OutputThe open-drain output XERR is used to report both of the TLC5940 error flags, TEF and LOD. During normaloperating conditions, the internal transistor connected to the XERR pin is turned off. The voltage on XERR ispulled up to VCC through an external pullup resistor. If TEF or LOD is detected, the internal transistor is turnedon, and XERR is pulled to GND. Since XERR is an open-drain output, multiple ICs can be OR'ed together andpulled up to VCC with a single pullup resistor. This reduces the number of signals needed to report a system error(see Figure 22).
To differentiate LOD and TEF signal from XERR pin, LOD can be masked out with BLANK = HIGH.
Table 1. XERR Truth TableERROR CONDITION ERROR INFORMATION SIGNALS
TEMPERATURE OUTn VOLTAGE TEF LOD BLANK XERRTJ < T(TEF) Don't Care L X H
HTJ > T(TEF) Don't Care H X L
OUTn > V(LED) L L HTJ < T(TEF) OUTn < V(LED) L H L
TLC5940SLVS515D –DECEMBER 2004–REVISED NOVEMBER 2015 www.ti.com
8.3.3 TEF: Thermal Error FlagThe TLC5940 provides a temperature error flag (TEF) circuit to indicate an overtemperature condition of the IC. Ifthe junction temperature exceeds the threshold temperature (160°C typical), TEF becomes H and XERR pingoes to low level. When the junction temperature becomes lower than the threshold temperature, TEF becomesL and XERR pin becomes high impedance. TEF status can also be read out from the TLC5940 status register.
8.3.4 LOD: LED Open DetectionThe TLC5940 has an LED-open detector that detects broken or disconnected LEDs. The LED open detectorpulls the XERR pin to GND when an open LED is detected. XERR and the corresponding error bit in the StatusInformation Data is only active under the following open-LED conditions.1. OUTn is on and the time tpd2 (1 μs typical) has passed.2. The voltage of OUTn is < 0.3 V (typical)
The LOD status of each output can be also read out from the SOUT pin. See STATUS INFORMATION OUTPUTsection for details. The LOD error bits are latched into the Status Information Data when XLAT returns to a lowafter a high. Therefore, the XLAT pin must be pulsed high then low while XERR is active in order to latch theLOD error into the Status Information Data for subsequent reading via the serial shift register.
8.3.5 Delay Between OutputsThe TLC5940 has graduated delay circuits between outputs. These circuits can be found in the constant currentdriver block of the device (see the functional block diagram). The fixed-delay time is 20 ns (typical), OUT0 has nodelay, OUT1 has a 20-ns delay, and OUT2 has a 40-ns delay, etc. The maximum delay is 300 ns from OUT0 toOUT15. The delay works during switch on and switch off of each output channel. These delays prevent largeinrush currents which reduces the bypass capacitors when the outputs turn on.
8.3.6 Output EnableAll OUTn channels of the TLC5940 can be switched off with one signal. When BLANK is set high, all OUTnchannels are disabled, regardless of logic operations of the device. The grayscale counter is also reset. WhenBLANK is set low, all OUTn channels work under normal conditions. If BLANK goes low and then back highagain in less than 300 ns, all outputs programmed to turn on still turn on for either the programmed number ofgrayscale clocks, or the length of time that the BLANK signal was low, which ever is lower. For example, if alloutputs are programmed to turn on for 1 ms, but the BLANK signal is only low for 200 ns, all outputs still turn onfor 200 ns, even though some outputs are turning on after the BLANK signal has already gone high.
Table 2. BLANK Signal Truth TableBLANK OUT0 - OUT15
TLC5940www.ti.com SLVS515D –DECEMBER 2004–REVISED NOVEMBER 2015
8.3.7 Setting Maximum Channel CurrentThe maximum output current per channel is programmed by a single resistor, R(IREF), which is placed betweenIREF pin and GND pin. The voltage on IREF is set by an internal band gap V(IREF) with a typical value of1.24 V. The maximum channel current is equivalent to the current flowing through R(IREF) multiplied by a factor of31.5. The maximum output current per channel can be calculated by Equation 6.
Imax must be set between 5 mA and 120 mA. The output current may be unstable if Imax is set lower than 5 mA.Output currents lower than 5 mA can be achieved by setting Imax to 5 mA or higher and then using dotcorrection.
Figure 1 shows the maximum output current IO versus R(IREF). R(IREF) is the value of the resistor between IREFterminal to GND, and IO is the constant output current of OUT0 to OUT15. A variable power supply may beconnected to the IREF pin through a resistor to change the maximum output current per channel. The maximumoutput current per channel is 31.5 times the current flowing out of the IREF pin.
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8.4 Device Functional Modes
8.4.1 Operating ModesThe TLC5940 has operating modes depending on the signals DCPRG and VPRG. Table 3 shows the availableoperating modes. The TPS5940 GS operating mode (see Figure 11) and shift register values are not definedafter power up. One solution to solve this is to set dot correction data after TLS5940 power-up and switch backto GS PWM mode. The other solution is to overflow the input shift register with 193 bits of dummy data and latchit while TLS540 is in GS PWM mode. The values in the input shift register, DC register and GS register areunknown just after power on. The DC and GS register values should be properly stored through the serialinterface before starting the operation.
Table 3. TLC5940 Operating Modes Truth TableSIGNAL
INPUT SHIFT REGISTER MODE DC VALUEDCPRG VPRG
L EEPROMGND 192 bit Grayscale PWM Mode
H DC RegisterL EEPROM
VCC 96 bit Dot Correction Data Input ModeH DC RegisterL EEPROM
V(VPRG) X EEPROM Programming ModeH Write dc register value to EEPROM. (Defaultdata: 3Fh)
8.4.2 Setting DOT CorrectionThe TLC5940 has the capability to fine adjust the output current of each channel OUT0 to OUT15 independently.This is also called dot correction. This feature is used to adjust the brightness deviations of LEDs connected tothe output channels OUT0 to OUT15. Each of the 16 channels can be programmed with a 6-bit word. Thechannel output can be adjusted in 64 steps from 0% to 100% of the maximum output current Imax. Dot correctionfor all channels must be entered at the same time. Equation 7 determines the output current for each output n.
where• Imax = the maximum programmable output current for each output.• DCn = the programmed dot correction value for output n (DCn = 0 to 63).• n = 0 to 15 (7)
Figure 14 shows the dot correction data packet format which consists of 6 bits x 16 channel, total 96 bits. Theformat is Big-Endian format. This means that the MSB is transmitted first, followed by the MSB-1, etc. The DC15.5 in Figure 14 stands for the 5th most significant bit for output 15.
Figure 14. Dot Correction Data Packet Format
When VPRG is set to VCC, the TLC5940 enters the dot correction data input mode. The length of input shiftregister becomes 96 bits. After all serial data are shifted in, the TLC5940 writes the data in the input shift registerto DC register when XLAT is high, and holds the data in the DC register when XLAT is low. The DC register is alevel triggered latch of XLAT signal. Since XLAT is a level-triggered signal, SCLK and SIN must not be changedwhile XLAT is high. After XLAT goes low, data in the DC register is latched and does not change. BLANK signaldoes not need to be high to latch in new data. XLAT has setup time (tsu1) and hold time (th1) to SCLK as shownin Figure 15.
TLC5940www.ti.com SLVS515D –DECEMBER 2004–REVISED NOVEMBER 2015
Figure 15. Dot Correction Data Input Timing Chart
The TLC5940 also has an EEPROM to store dot correction data. To store data from the dot correction register toEEPROM, DCPRG is set to high after applying VPRG to the VPRG pin. Figure 16 shows the EEPROMprogramming timings. The EEPROM has a default value of all 1 s.
TLC5940SLVS515D –DECEMBER 2004–REVISED NOVEMBER 2015 www.ti.com
8.4.3 Setting GrayscaleThe TLC5940 can adjust the brightness of each channel OUTn using a PWM control scheme. The use of 12 bitsper channel results in 4096 different brightness steps, respective 0% to 100% brightness. Equation 8 determinesthe brightness level for each output n.
where• GSn = the programmed grayscale value for output n (GSn = 0 to 4095)• n = 0 to 15• Grayscale data for all OUTn (8)
Figure 18 shows the grayscale data packet format which consists of 12 bits x 16 channels, totaling 192 bits. Theformat is Big-Endian format. This means that the MSB is transmitted first, followed by the MSB-1, etc.
Figure 18. Grayscale Data Packet Format
When VPRG is set to GND, the TLC5940 enters the grayscale data input mode. The device switches the inputshift register to 192-bit width. After all data is clocked in, a rising edge of the XLAT signal latches the data intothe grayscale register (see Figure 11). New grayscale data immediately becomes valid at the rising edge of theXLAT signal; therefore, new grayscale data should be latched at the end of a grayscale cycle when BLANK ishigh.The first GS data input cycle after dot correction requires an additional SCLK pulse after the XLAT signal tocomplete the grayscale update cycle. All GS data in the input shift register is replaced with status informationdata (SID) after updated the grayscale register.
8.4.4 Status Information OutputThe TLC5940 does have a status information register, which can be accessed in grayscale mode (VPRG=GND).After the XLAT signal latches the data into the GS register the input shift register data will be replaced with statusinformation data (SID) of the device (see Figure 18). LOD, TEF, and dot correction EEPROM data(DCPRG=LOW) or dot correction register data (DCPRG=HIGH) can be read out at SOUT pin. The statusinformation data packet is 192 bits wide. Bits 0-15 contain the LOD status of each channel. Bit 16 contains theTEF status. If DCPRG is low, bits 24-119 contain the data of the dot-correction EEPROM. If DCPRG is high, bits24-119 contain the data of the dot-correction register.The remaining bits are reserved. The complete statusinformation data packet is shown in Figure 19.
SOUT outputs the MSB of the SID at the same time the SID are stored in the SID register, as shown Figure 20.The next SCLK pulse, which will be the clock for receiving the SMB of the next grayscale data, transmits MSB-1of SID. If output voltage is < 0.3 V (typical) when the output sink current turns on, LOD status flage becomesactive. The LOD status flag is an internal signal that pulls XERR pin down to low when the LOD status flagbecomes active. The delay time, tpd2 (1 μs maximum), is from the time of turning on the output sink current tothe time LOD status flage becomes valid. The timing for each channel's LOD status to become valid is shifted bythe 30-ns (maximum) channel-to-channel turn-on time. After the first GSCLK goes high, OUT0 LOD status isvalid; tpd3 + tpd2 = 60 ns + 1 μs. OUT1 LOD status is valid; tpd3 + td + tpd2 = 60 ns + 30 ns + 1 μs = 1.09 μs.OUT2 LOD status is valid; tpd3 + 2*td + tpd2 = 1.12 μs, and so on. It takes 1.51 μs maximum (tpd3 + 15*td +tpd2) from the first GSCLK rising edge until all LOD become valid; tsuLOD must be > 1.51 μs (see Figure 20) toensure that all LOD data are valid.
TLC5940www.ti.com SLVS515D –DECEMBER 2004–REVISED NOVEMBER 2015
Figure 19. Status Information Data Packet Format
Figure 20. Readout Status Information Data (SID) Timing Chart
8.4.5 Grayscale PWM OperationThe grayscale PWM cycle starts with the falling edge of BLANK. The first GSCLK pulse after BLANK goes lowincreases the grayscale counter by one and switches on all OUTn with grayscale value not zero. Each followingrising edge of GSCLK increases the grayscale counter by one. The TLC5940 compares the grayscale value ofeach output OUTn with the grayscale counter value. All OUTn with grayscale values equal to the counter valuesare switched off. A BLANK=H signal after 4096 GSCLK pulses resets the grayscale counter to zero andcompletes the grayscale PWM cycle (see Figure 21). When the counter reaches a count of FFFh, the counterstops counting and all outputs turn off. Pulling BLANK high before the counter reaches FFFh immediately resetsthe counter to zero.
TLC5940www.ti.com SLVS515D –DECEMBER 2004–REVISED NOVEMBER 2015
9 Application and Implementation
NOTEInformation in the following applications sections is not part of the TI componentspecification, and TI does not warrant its accuracy or completeness. TI’s customers areresponsible for determining suitability of components for their purposes. Customers shouldvalidate and test their design implementation to confirm system functionality.
9.1 Application InformationThe device is a 16-channel, constant sink current, LED driver. This device can be connected in series to drivemany LED lamps with only a few controller ports. Output current control data, dot correction data and PWMcontrol data can be written from the SIN input terminal.
9.2 Typical Application
Figure 22. Cascading Devices
9.2.1 Design RequirementsFor this design example, use the input parameters shown in Table 4.
Table 4. Design ParametersPARAMETERS VALUES
VCC input voltage range 3.0 V to 5.5 VLED lamp (VLED) input voltage range >Maximum LED forward voltage (VF) + IC knee voltage
SIN, SCLK, XLAT, GSCLK, and BLANK voltage range Low level = GND, High level = VCC
TLC5940SLVS515D –DECEMBER 2004–REVISED NOVEMBER 2015 www.ti.com
9.2.2 Detailed Design Procedure
9.2.2.1 Serial Data Transfer RateFigure 22 shows a cascading connection of n TLC5940 devices connected to a controller, building a basicmodule of an LED display system. The maximum number of cascading TLC5940 devices depends on theapplication system and is in the range of 40 devices. Equation 9 calculates the minimum frequency needed:
where• f(GSCLK): minimum frequency needed for GSCLK• f(SCLK): minimum frequency needed for SCLK and SIN• f(update): update rate of whole cascading system• n: number cascaded of TLC5940 device (9)
9.2.2.2 Grayscale (GS) DataThere are a total of 16 sets of 12-bit GS data for the PWM control of each output. Select the GS data of eachLED lamp and write the GS data to the register following the signal timing.
9.2.3 Application Curve
Figure 23. Output Waveform with Different Grayscale PWM Data
TLC5940www.ti.com SLVS515D –DECEMBER 2004–REVISED NOVEMBER 2015
10 Power Supply RecommendationsThe VCC power supply voltage should be decoupled by placing a 0.1uF ceramic capacitor close to VCC pin andGND plane. Depending on panel size, several electrolytic capacitors must be placed on board equally distributedto get a well regulated LED supply voltage (VLED). VLED voltage ripple should be less than 5% of its nominalvalue. Furthermore, the VLED should be set to the voltage calculated by equation:
VLED > VF + 0.4V ( 10mA constant current example) where Vf = maximum forward voltage of all LEDs.
11 Layout
11.1 Layout Guidelines1. Place the decoupling capacitor near the VCC pin and GND plane.2. Place the current programming resistor Riref close to IREF pin and IREFGND pin.3. Route the GND pattern as widely as possible for large GND currents.4. Routing wire between the LED cathode side and the device OUTn pin should be as short and straight as
possible to reduce wire inductance.5. When several ICs are chained, symmetric placements are recommended.
TLC5940SLVS515D –DECEMBER 2004–REVISED NOVEMBER 2015 www.ti.com
11.3 Power Dissipation CalculationThe device power dissipation must be below the power dissipation rating of the device package to ensure correctoperation. Equation 10 calculates the power dissipation of device.
where• VCC: device supply voltage• ICC: device supply current• VOUT: TLC5940 OUTn voltage when driving LED current• IMAX: LED current adjusted by R(IREF) Resistor• DCn: maximum dot correction value for OUTn• N: number of OUTn driving LED at the same time• dPWM: duty cycle defined by BLANK pin or GS PWM value (10)
TLC5940www.ti.com SLVS515D –DECEMBER 2004–REVISED NOVEMBER 2015
12 Device and Documentation Support
12.1 Community ResourcesThe following links connect to TI community resources. Linked contents are provided "AS IS" by the respectivecontributors. They do not constitute TI specifications and do not necessarily reflect TI's views; see TI's Terms ofUse.
TI E2E™ Online Community TI's Engineer-to-Engineer (E2E) Community. Created to foster collaborationamong engineers. At e2e.ti.com, you can ask questions, share knowledge, explore ideas and helpsolve problems with fellow engineers.
Design Support TI's Design Support Quickly find helpful E2E forums along with design support tools andcontact information for technical support.
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12.3 Electrostatic Discharge CautionThese devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foamduring storage or handling to prevent electrostatic damage to the MOS gates.
12.4 GlossarySLYZ022 — TI Glossary.
This glossary lists and explains terms, acronyms, and definitions.
13 Mechanical, Packaging, and Orderable InformationThe following pages include mechanical, packaging, and orderable information. This information is the mostcurrent data available for the designated devices. This data is subject to change without notice and revision ofthis document. For browser-based versions of this data sheet, refer to the left-hand navigation.
TLC5940PWP ACTIVE HTSSOP PWP 28 50 Green (RoHS& no Sb/Br)
CU NIPDAU Level-2-260C-1 YEAR -40 to 85 TLC5940
TLC5940PWPG4 ACTIVE HTSSOP PWP 28 50 Green (RoHS& no Sb/Br)
CU NIPDAU Level-2-260C-1 YEAR -40 to 85 TLC5940
TLC5940PWPR ACTIVE HTSSOP PWP 28 2000 Green (RoHS& no Sb/Br)
CU NIPDAU Level-2-260C-1 YEAR -40 to 85 TLC5940
TLC5940PWPRG4 ACTIVE HTSSOP PWP 28 2000 Green (RoHS& no Sb/Br)
CU NIPDAU Level-2-260C-1 YEAR -40 to 85 TLC5940
TLC5940RHBR ACTIVE VQFN RHB 32 3000 Green (RoHS& no Sb/Br)
CU NIPDAU Level-2-260C-1 YEAR -40 to 85 TLC5940
TLC5940RHBRG4 ACTIVE VQFN RHB 32 3000 Green (RoHS& no Sb/Br)
CU NIPDAU Level-2-260C-1 YEAR -40 to 85 TLC5940
(1) The marketing status values are defined as follows:ACTIVE: Product device recommended for new designs.LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design.PREVIEW: Device has been announced but is not in production. Samples may or may not be available.OBSOLETE: TI has discontinued the production of the device.
(2) Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check http://www.ti.com/productcontent for the latest availabilityinformation and additional product content details.TBD: The Pb-Free/Green conversion plan has not been defined.Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements for all 6 substances, including the requirement thatlead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes.Pb-Free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and package, or 2) lead-based die adhesive used betweenthe die and leadframe. The component is otherwise considered Pb-Free (RoHS compatible) as defined above.Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame retardants (Br or Sb do not exceed 0.1% by weightin homogeneous material)
(3) MSL, Peak Temp. - The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature.
(4) There may be additional marking, which relates to the logo, the lot trace code information, or the environmental category on the device.
(5) Multiple Device Markings will be inside parentheses. Only one Device Marking contained in parentheses and separated by a "~" will appear on a device. If a line is indented then it is a continuationof the previous line and the two combined represent the entire Device Marking for that device.
(6) Lead/Ball Finish - Orderable Devices may have multiple material finish options. Finish options are separated by a vertical ruled line. Lead/Ball Finish values may wrap to two lines if the finishvalue exceeds the maximum column width.
Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on informationprovided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken andcontinues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals.TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release.
In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis.
OTHER QUALIFIED VERSIONS OF TLC5940 :
• Enhanced Product: TLC5940-EP
NOTE: Qualified Version Definitions:
• Enhanced Product - Supports Defense, Aerospace and Medical Applications
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